Pex Tube Heating Knocking Sound
I have a hot water heating system that uses pex tubing. We have an annoying knocking sound whenever the system kicks on. I realize this is the tube expanding and contracting. Is there anyway to stop this noise. Do I need to bleed the system? If so, how do you do this. It’s almost as…
I have a hot water heating system that uses pex tubing. We have an annoying knocking sound whenever the system kicks on. I realize this is the tube expanding and contracting. Is there anyway to stop this noise. Do I need to bleed the system? If so, how do you do this. It’s almost as loud as the clanging of the pipes at my old house. Thought the pex tubing wold eliminate this. Any help would be appreciated.
Instead of graphite how about the old reliable: baby powder?
graphite is pretty inert, but I guess better safe than sorry.
Do not put a lubricant on PEX tubing unless you check with the tubing manufacturer.
Polyethylene reacts to many different chemicals and compounds in a not-so-good way.
Was this staple-up radiant tubing, meaning was it installed between joists under the floor? If so, the noise is most likely the pex rubbing against the wood, which occurs where the tube is threaded through the small hole between joists. If it the tubing can be accessed the knocking can be solved with graphite lubrication in these spots.
You would have to find the part of the tubing that’s making noise and give it some room to expand.
This is common with PEX when it is secured to wood flooring.
It may go away on its own over time, but there’s nothing you can do except reposition the tube.